Technical Abstract:
Rangeland health and soil quality are frequently defined in terms of the capacity of the land to conserve soil and water resources, cycle nutrients and support productive plant communities. Rangeland monitoring programs in most countries have traditionally focused, almost exclusively, on plant community composition. An implicit assumption is that other properties and processes are correlated with vegetation, so measurements are unnecessary. In many cases, however, soil degradation or improvement can occur in the absence of easily detectable vegetation changes until a threshold is crossed resulting in dramatic and frequently irreversible changes in plant community composition. We suggest that easily-measured soil properties can serve as early-warning indicators of potential transitions between vegetation states in rangeland ecosystems. These indicators and associated vegetation measurements are by no means universal. Both the selections of quantitative indicators and the identification of appropriate monitoring points depend on monitoring objectives and resource availability. Rapid, qualitative indicators can aid in the design of a quantitative monitoring program. They can also be applied together with quantitative indicators to aid interpretation. We describe how quantitative and qualitative soil and vegetation indicators can be used together to monitor rangeland health.